Fibeabm and allot fob making sakx



Reiseued Feb. 22,1921.

UNITED STATES PATENT- OFFICE.

FRANK A. I'AHBEN'WALD, OI CHICAGO, ILLINOIS.

FIREARM AND ALLOY FOR MAKING SAME.

I No Drawing. Original No. 1,846,188, dated July 13, 1920, Serial lI'o. 319,822, filed August 25, 1918.

Application for reissue filed October 15, 1926. Serial No. 141,871.

This invention relates to firearms and ordnance and has for its particular object the provision of a metallic alloy for use in the construction of the same which shall be more resistant to corrosion by the combustion products of the explosive as well as less corroded by atmospheric conditions, saltsolution (such as sea water or sweaty hands) than anything previously used for the purpose, as well as having sufiicient mechanical strength to endure the strains to which such devices are subjected and at the same time being 'sufliciently soft and workable for manufacturing purposes;

It is well known thatpowder gases particularly those of the present day smokeless and high explosive powders are extremely'corrosiv e to steel barrels so that the latter become rapidly etched and pitted. This circumstance has greatly shortened the life of sporting arms and has rendered very onerous the maintenance of militarv arms of all c alibers, since not only have the metals heretofore employed 'sufiered; greatly by the instant erosion of the hot gases but the powder residues are of an equally great corrosiveness andcannot be removed bv mere physical means nor even by a single application of chemicals. .Unless such a firearm be cleaned within at least an hour after each shot. the barrel interior becomes noticeably etched, 'and even a few very small pits seriously im,- pairs the accuracy of the gun. Likewise the exteriors of the barrels and the surfaces of '35 the operating mechanism becomerapidly corroded by'atmospheric influences and skin contact unless frequently oiled. Furthermore, mosthigh velocity rifle bullets used at the presentday are jacketed with some alloy which will keen the lead from melting and will engage the rifling properly. Most of these jacket materials possess such an aflinity for the iron of which rifle barrelshave heretofore been made as to alloy therewith under the influence of high'temperature,velocity and pressure, thus producing thephenomenon known as-m etal fouling, which means a slow accretion inside the barrel, of substance taken from the bullets which always interferes seriously with-the accuracygroup metals.

anld frequently leads to bursting of the barre Numerous alloys have heretofore been known which would resist the chemical action to the necessary extent, (such as alloys of platinum,gold-palladium, and the like precious metals), but the physical requirements of'firearms metal are also peculiarl exacting since it must be sufficiently so and uniform to permit of ready boring and rifling of the barrel and fashioning of the operating mechanism, and yet possess sufficient toughness and mechanical strength to resist the explosion pressures-and the mishaps to which such devices are necessarily subjected use.

I The objects of my invention are, therefore, the provision of an alloy for the purposes stated having the re uisite chemical resistivity coupled with t e necessary physical strength; the provision of an alloy which shall not be subject to metal fouling; the

revision of an alloy which can be readily orged, machined and worked into sha e; the provision of an alloy of reasonably ow intrinsic valve and containing only readily available ingredients; the provision of an alloy which can be: made by a simple and workable process; while further objects and advantages of my invention will become apparent as the description proceeds.

My improved alloy consists essentially of iron com ined with one or more chromium Carbon and silicon may be present in case their quantities are small, say .5% or less; a small amount of manganese is preferably employed because of its value in scavengin oxy en and sulphur and because of the fact t at better castings are secured with its use. The tensile'stren the alloy can be increased slightly by t e addition of a small amount of copper, tanta As examples of alloys which embody my invention, I will instance the following, the first column indicating the preferred composition within that. group and the parenthesis indicating the permissible Variations.

It will be understood that the foregoing formulas are not intended to include all the ingredients present in the alloys. since small amounts of carbon, silicon, and manganese will almost always be present at least as impurities, and small quantities of certain additional metals may sometimes be added such as copper etc. as has already been suggested. It is only necessary that the percentage of carbon and silicon be kept sufficiently low, such as .5% or less of each, to preventthe metal from beingtoo hard to work, and that sulphur and phosphorus be avoided. I a

When one adds to the corrosion resisting requirements and the strength and hardness limitations heretofore described the further requirement of a low intrinsic value it is found that the alloy which best fulfills all these demands is one falling within group a above indicated, namely a binary alloy of iron and chromium which contains no other element or ingredient at least in a quantity sufficient to exhibitany substantial physical or chemical efi'ect. Hence the carbon must be kept-low, of this element being the uppermost permissible limit and being much better. Also any admixture of nickel or cobalt is undesirable for the same reason, namely an increase 'in hardness. although this effect does not become noticeable with a nickel or cobalt content of less than about It can be made with comparative ease in the electric furnace or by the aluminothermic method it makes a good casting, can readily be forged or rolled at a bright red heat, and can be bored. turned, rifled and shaped Without ditficulty. The gases and residues of smokeless powder do not etch it even in days of neglect, rain does not rust it, and polished barrels buried in the ground for weeks exhibit only a slight superficial tarnish which can be wiped ofl with the hand. Bullet jackets of iron, nickel, or their alloys do'not foul it. and its tensile strength is so high that it compares well with the steels ordinarily used.

This alloy is good enough for most purposes and has the advantages of being much cheaper a much more easily rolled and ma.- chincd' than any of the more complicated, ternary or quaternary alloys. It can be slightly improved by the addition of a little molybdenum'or tungsten, which have the effect of increasing the chemical resistivity without proportionately increasing the hardness.

The substitution of nickel for iron in a gives 7) which is superior in the same proportion that nickel is superior to iron in chemical resistivity. Owing to the hardening effectof chromium thereon the proportion of the latter is decreased. Iron must also be omitted because of its hardening efltect when used in'conjunction with nickel. It will be understood that cobalt can be employed in substitution for nickel although no advantage in its use ofisets its high price.

If'tungsten or molybdenum be employed in place of chromium in b, I secure the alloy shown at c which is also hard, strong and chemically resistant; or if the chromium in a is replaced by tungsten or molybdenum I secure the alloy shown at (Z which is also of value for firearms. In these cases the amount of the tungsten-like metal is decreased owing to its hardening eii'ect.

I find that the essential elements are those contained in-the iron and chromium groups of the eriodic table and that at least one metal from each group should be used: also that only a single iron group metal should be used owing to their mutual hardening effect when used together and that the chromium group metal should occur to an amount of at least about 5% and may go as high as 40% when the iron group metal is iron alone and the chromium group metal be chromium alone without rendering the allov too hard to work.

It will be understood that While my irnproved alloy isspecially devised for manually portable arms such as rifles and shotguns it is equally good for pocket devices such as revolvers or for ordnance of large sizes; that the barrels can be made from a, single homogeneous piece of the material, or that a composite ingot may be made, or a built up barrel employing my improved alloy as a lining; that my alloy can be used for lock mechanisms equally with the barrels; and that I desire my claims taken in the broadest sense that their language will support.

Having thus described my invention what I claim is:

l. A firearm barrelmade from an alloy of one iron group metal combined With one or more chromium group metals. any second iron group metal being restricted to less than it and carbon being not over 2. A firearm barrel made from an alloy of one iron group metal combined with one or more chromium group metals, the latter being present to an amount of at least 5%, and no other substance being present in an amount greater than 3. A firearm barrel made from an alloy of iron together with at least one chromium group metal, nickel if present at all being restricted to less than 4. A firearm barrel made froman allo of two iron group metals together with c romium and another metal from the chromium group and less than of carbon.

5. A firearm barrel made from an alloy containing at least 5% of chromium, less than .5% of nickel and more than 60% of lI'OIl.

6. A firearm barrel made from an alloy containing between 5% and of one or more metals of the chromium group combined with a metal of the iron group, not more than .5% of the whole alloy being nickel.

7. A firearm having a barrel composed of or lined with an alloy of iron,.'and chromium wherein the chromium comprises not less than about 10% of the whole, and carbon not over .5% of the whole.

8. A firearm having parts made of an al- 10y containing not less than about 80% of iron alloyed with not more than .5% of nickel and at least 8% of chromium.

9. A firearm having parts made of an alby comprising between 8% and 20% chromium, together 'with between about 80% and 92% iron, and other elements, if present, being restricted to less than about .5%.

10. A firearm having a barrel made of an alloy containing essentially iron and chromium, the iron constituting at least 80% and the chromium at least 10% of the alloy, and no other element being present in sufiicient amount to exert any appreciable hardening effect.

11. .A firearm having parts made of an 7 alloy containing less than 90% of iron combined with at least 5% of a metal from the chromium group, and excluding any substantial percentage of any other iron group metal, carbon being restricted to an amount of or lined with a binary alloy contalning between 30% and 90% of iron, and at least 10% of chromium.

13. A firearm having a barrel composed of or lined with a binary alloy containing not over 90% of iron and not less than 10% of chromium. v

14. A firearm having a barrel composed of or lined with an' alloy containing a preponderance of iron group metals together with from 5% to 20% of metals below chromium in the chromium group.

15. A firearm having a barrel composed of or lined with an alloy containing a single iron group metal to a total of from 75% to 95%,, the balance being chromium group metals and carbon being restricted to less than 16. A firearm having a barrel composed of or lined with an alloy containing a single iron group metal to a total proportion of between 7 5% and 90% combined with chromium group metals, chromium itself con stituting at least one-halfof the balance.

17. A firearm barrel made of an alloy containing iron combined with at least ten percent of chromium and less than .5% of any other substance or substances.

18. A firearm barrel made of an alloy con-- taining between about twenty-five percent and about ninety percent of iron, the bal-\ ance being chromium and carbon being present to an amount not greater than two tenths of one percent.

'19. A firearm barrel made of an alloy consisting essentially of iron with either or both nickel and (or) chromium,'the highest limit of chromium being about twenty-five percent and the highest limit of iron being about ninety percent the highest limit of nickel being about one-half percent and the lowest limit of chromium being not less than about ten percent.

FRANK A. FAH-RENWALD. 

